TTY patches for 2.6.33-git
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From: Andrew Morton on 12 Dec 2009 05:40 On Sat, 12 Dec 2009 11:10:32 +0100 Ingo Molnar <mingo(a)elte.hu> wrote: > > * Andrew Morton <akpm(a)linux-foundation.org> wrote: > > > Seems to be quite .config-dependent. > > My theory is that it's a race and that it's thus timing dependent. TTY > SMP details get stressed most during a particular point during bootup, > when all the mingetty's are starting up all at once and race with each > other. > > If you are lucky to not hit the bug then, then the likelyhood is much > lower later on. > > It would be nice if Alan posted his TTY stress-testing code. It could > potentially make this bug bisectable. > I'm surprised that lockdep didn't notice that ab/ba I thought I saw. Maybe the do_tty_hangup()->tty_fasync() never happens. The machine I can reproduce this on is at work and I'm not, until Monday. I'd try removing the files_lock() calls from tty_io.c, see if that helps. I had [ 71.553228] Warning: dev (tty1) tty->count(7) != #fd's(6) in tty_release_dev come out once, then it went away. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Andrew Morton on 12 Dec 2009 05:50 On Sat, 12 Dec 2009 11:15:51 +0100 Ingo Molnar <mingo(a)elte.hu> wrote: > i'm testing the series of 5 reverts below. It's looking good so far. You > might want to try them - how quickly can you reproduce the hangs? Immediately, with http://userweb.kernel.org/~akpm/config-akpm2.txt -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Alan Cox on 12 Dec 2009 05:50 On Sat, 12 Dec 2009 09:46:11 +0100 Ingo Molnar <mingo(a)elte.hu> wrote: > > * Greg KH <gregkh(a)suse.de> wrote: > > > Here's the big TTY patchset for your .33-git tree. > > FYI, one of the changes in this tree is causing lockups on x86. > > Config attached. > > Possible suspects would one of these: > > 36ba782: tty: split the lock up a bit further > 5ec93d1: tty: Move the leader test in disassociate > 38c70b2: tty: Push the bkl down a bit in the hangup code > f18f949: tty: Push the lock down further into the ldisc code > eeb89d9: tty: push the BKL down into the handlers a bit > > as they deal with locking details and are fresher than two weeks. Any diagnostics with the lockup or just a system hang ? You can pop back those five and if the lockup then vanishes those are ones trying to work on hangup and BKL rather than security fixes so can just get punted to next release -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Ingo Molnar on 12 Dec 2009 05:50 * Alan Cox <alan(a)lxorguk.ukuu.org.uk> wrote: > On Sat, 12 Dec 2009 09:46:11 +0100 > Ingo Molnar <mingo(a)elte.hu> wrote: > > > > > * Greg KH <gregkh(a)suse.de> wrote: > > > > > Here's the big TTY patchset for your .33-git tree. > > > > FYI, one of the changes in this tree is causing lockups on x86. > > > > Config attached. > > > > Possible suspects would one of these: > > > > 36ba782: tty: split the lock up a bit further > > 5ec93d1: tty: Move the leader test in disassociate > > 38c70b2: tty: Push the bkl down a bit in the hangup code > > f18f949: tty: Push the lock down further into the ldisc code > > eeb89d9: tty: push the BKL down into the handlers a bit > > > > as they deal with locking details and are fresher than two weeks. > > Any diagnostics with the lockup or just a system hang ? None that i've captured (the hang is silent) but Andrew posted some. Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Ingo Molnar on 12 Dec 2009 06:00
* Andrew Morton <akpm(a)linux-foundation.org> wrote: > On Sat, 12 Dec 2009 11:15:51 +0100 Ingo Molnar <mingo(a)elte.hu> wrote: > > > i'm testing the series of 5 reverts below. It's looking good so far. You > > might want to try them - how quickly can you reproduce the hangs? > > Immediately, with http://userweb.kernel.org/~akpm/config-akpm2.txt Ok. The lockups i saw went away with the 5 reverts i posted. I'll keep testing that over the weekend - that should narrow down the range very precisely. Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |